Plasma display panel for multi-screen

ABSTRACT

A plasma display panel for a multi-screen having a bonding portion disposed within a display area provided by upper and lower plates, the bonding portion being constituted by thin side wall members and a thin bonding member to have a minimized width. Where a multi-screen is fabricated using plasma display panels including the bonding portion, it is possible to minimize generation of mosaic pattern, thereby avoiding any picture distortion phenomenon.

TECHNICAL FIELD

The present invention relates to a plasma display panel for amulti-screen constituted by a plurality of unit plasma display panelsassembled together, and more particularly to a plasma display panel fora multi-screen capable of minimizing the generation of a mosaic patternand a picture distortion on the entire multi-screen by minimizing thesize of a connection boundary area formed between adjacent unit plasmadisplay panels connected to each other to constitute the multi-screen.

BACKGROUND ART

To manufacture an image display device with a large screen having a sizeof several hundred inches, a multi-screen system is generally used, inwhich a screen is constituted by connecting a plurality of unit displaydevices together such that adjacent unit displays are in contact witheach other at their facing edges. This is because it is difficult tofabricate a large screen using a single display device in terms oftechnology and economy.

Where a large screen is fabricated using plasma display panels, it issuitable to use the multi-screen system because of the above-mentionedreason. Plasma display panels have a superior non-linearity over otherplanar displays. Where these plasma display panels are used toconstitute a multi-screen, accordingly, they can exhibit a continuitybetween adjacent unit screens, thereby providing a screen with goodquality as compared to other display devices.

Even in the multi-screen constituted by the plasma display panels,however, it is difficult to avoid a connection boundary area formedbetween adjacent unit plasma display panels each constituting a partialscreen. As a result, a mosaic pattern is formed on the entire screen.The reason why the connection boundary area is formed is because eachunit plasma display panel has a non-display area at its sealing portionfor bonding upper and lower plates of the unit plasma display panel dueto a certain thickness of the sealing portion. Since the thickness ofthe sealing portion is increased twice when adjacent unit plasma displaypanels are connected to each other, a connection boundary area disablinga display on the screen is formed at the connection region betweenadjacent unit plasma display panels.

In spite of the non-linearity characteristic of plasma display panels,the mosaic pattern causes a picture distortion phenomenon to occur uponconnecting pictures. As a result, the entire picture becomes unnatural,thereby resulting in a degradation in picture quality. In particular,where an oblique line is displayed such that it extends over adjacentoutermost display cells of adjacent unit plasma display panels, itsdisplay becomes inaccurate because a picture distortion occurs due tothe thickness of the connection boundary area, in spite of the superiornon-linearity characteristic of the plasma display panels.

It is apparent that such a mosaic pattern generated due to theconnection boundary area serves to degrade the quality of the entirescreen. It is therefore desirable to prevent the generation of such amosaic pattern as much as possible. In order to minimize the picturedistortion occurring due to the connection boundary area, it is requiredto reduce the width of the connection boundary area. For this, there hasbeen proposed a method for bonding upper and lower plates of each unitplasma display panel at their edges using a bonding glass plate.However, this method is difficult to efficiently accomplish the purposefor eliminating or reducing the connection boundary area. This isbecause the bonding glass plate should have a certain thickness toprovide reliability and workability.

Another method has also been proposed which involves attaching a bondingmember along side edges of the upper and lower plates and then pressingthe bonding member to reduce the thickness of the bonding member. Inthis method, however, the bonding member should also have a certainthickness on the outside of the upper and lower plates. In other words,it is difficult to efficiently reduce the connection boundary area byusing this method.

Therefore, an object of the invention is to provide a unit plasmadisplay panel capable of minimizing the size of a connection boundaryarea formed between adjacent unit plasma display panels connected toeach other to constitute a multi-screen, thereby minimizing thegeneration of a mosaic pattern on the entire multi-screen.

DISCLOSURE OF THE INVENTION

In accordance with the present invention, this object is accomplished byproviding a plasma display panel for a multi-screen comprising: an upperplate and a lower plate; a plurality of cathode electrodes and anodeelectrodes arranged so that they are spaced facing each other betweenthe upper and lower plates; a plurality of inner display cells definedwithin a display area provided between the upper and lower plates by aplurality of spaced first partition members arranged between the upperand lower plates, respectively, the inner display cells having the samearea; outermost display cells arranged along edges of the upper andlower plates, each of the outermost display cells being defined betweenside wall means provided along the edges of the upper and lower platesand a second partition member arranged between the upper and lowerplates and spaced from the side wall means inwardly of the upper andlower plates, the second partition member having a reduced thicknessover that of each first partition member; and bonding means arrangedoutwardly of the side wall means and provided with an outer surfacevertically aligned with the edges of the upper and lower plates, thebonding means being adapted to bond the upper and lower plates to eachother.

In accordance with a preferred embodiment of the present invention, thebonding means forming an outer boundary area of each outermost displaycell is arranged within the outermost display cell without beingarranged outwardly of the display area. Preferably, each of theoutermost display cells has a size smaller than the size of each innerdisplay cell by a size almost identical to the size of the bondingmeans. Where a multi-screen is constituted by connecting a plurality ofunit plasma display panels together such that adjacent unit plasmadisplay panels are in contact with each other at their facing edges,accordingly, it is possible to avoid any picture distortion phenomenonbetween adjacent unit plasma display panels. It is also possible tominimize generation of a connection boundary area.

In accordance with another embodiment of the present invention, thesecond partition member isolating each outermost display cell fromdisplay cells adjacent thereto is reduced in width at its portion facingthe outermost display cell to partially compensate the reduced size ofthe outermost display cell. With such a construction, it is possible topartially compensate the discharge area of the outermost display cellreduced due to the bonding means arranged within the outermost displaycell.

BRIEF DESCRIPTION OF DRAWINGS

The above and other objects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a plan view schematically illustrating a multi-screenconstituted by conventional plasma display panels;

FIG. 2 is a plan view similar to FIG. 1, schematically illustrating amulti-screen constituted by plasma display panels in accordance with thepresent invention;

FIG. 3 is a cross-sectional view of the plasma display panel shown inFIG. 2, taken along in an X-axis direction; and

FIG. 4 is a cross-sectional view of the plasma display panel, takenalong in a Y-axis direction.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 is a schematic view illustrating a multi-screen constituted byconventional plasma display panels. As shown in FIG. 1, each of the unitplasma display panels 1 includes a bonding member 3 for bonding theupper and lower plates to each other. The bonding member 3 extends alongouter edges of outermost display cells 2 thereof, that is, edges ofupper and lower plates. Although not shown, the upper plate of each unitplasma display panel 1 generally has an area larger than that of thelower plate. In other words, the upper plate extends outwardly beyondthe lower plate. The bonding member 3 is disposed between the end of thelower plate and the portion of the upper plate extending beyond the endof the lower plate, to firmly fix the edges of the upper and lowerplates. Due to the provision of this bonding member 3, the portion ofthe upper plate extending beyond the lower plate is left as a marginarea where any display function is not performed at all. Such a marginarea does not interfere with the display function of the screen wherethe screen is constituted by only one plasma display panel. Where amulti-screen is constituted by connecting a plurality of unit plasmadisplay panels 1 together such that adjacent unit plasma display panelsare in contact with each other at their facing edges as shown in FIG. 1,however, the above-mentioned problem is generated because a connectionboundary area is formed on the entire screen due to the margin area. Forexample, when an oblique line is displayed on the multi-screen shown inFIG. 1, it has no continuity due to the thickness of the connectionboundary area formed due to the bonding member 3, as indicated by thecircles 5 in FIG. 1. As a result, the picture quality is degraded.

Another conventional method has also been proposed, wherein upper andlower plates having the same size are used. In accordance with thismethod, the bonding member 3 has an outer surface vertically alignedwith the outer edges of the upper and lower plates. In this case,however, there is no means for compensating the size of the outermostdisplay cells. As a result, this method has a problem that the outermostdisplay cells should have a size larger than those of inner displaycells.

FIG. 2 illustrates a multi-screen constituted by connecting a pluralityof unit plasma display panels together such that adjacent unit plasmadisplay panels are in contact with each other at their facing edges inaccordance with a preferred embodiment of the present invention.

As shown in FIG. 2, each of the unit plasma display panels, which aredenoted by the reference numeral 10, has a margin area narrower thanthat of the conventional plasma display panel 1, in accordance with theembodiment of the present invention. Accordingly, it is possible toavoid the picture discontinuity inevitably generated due to thethickness of the boundary area when an oblique line is displayed suchthat it extends over adjacent unit plasma display panels 10 as shown inFIG. 2. This results in a great reduction in picture distortionphenomenon, thereby improving the picture quality.

FIG. 3 is a cross-sectional view of the plasma display panel 10 shown inFIG. 2, taken along in an X-axis direction. On the other hand, FIG. 4 isa cross-sectional view of the plasma display panel, taken along in aY-axis direction.

As shown in FIGS. 3 and 4, the plasma display panel 10 basicallyincludes upper and lower plates 11 and 12 having the same size, that is,the same longitudinal and lateral lengths. Between the upper and lowerplates 11 and 12, a plurality of spaced cathode electrodes 13 and aplurality of spaced anode electrodes 14 are arranged such that theycross each other. These electrodes 13 and 14 serve to perform adischarge function to display images on corresponding display cells,respectively. The plasma display panel 10 is divided into display cells15 each constituting a unit pixel by a plurality of first partitionmembers 16. In this arrangement, it should be noted that the displaycells 15 defined by the partition members 16 do not include theoutermost display cells 15A of the plasma display panel 10. Each of theoutermost display cells 15A is defined by a second partition member 16Aand side wall members 17 constituting a part of the side wall of theplasma display panel 10. Desirably, the side wall members 17 are formedalong the edges of the upper and lower plates 11 and 12 such that theyhave a small thickness, respectively, using a printing technique.

Preferably, the side wall mender 17 formed on the lower plate 12 isarranged at a place shifted a small distance from the edge of the lowerplate 12 inwardly of the plasma display panel 10, as shown in FIG. 3, sothat the outer surface bonding portion 20 of the plasma display panelcan be vertically aligned with the edges of the upper and lower plates11 and 12, as will be described hereinafter. The side wall 17 formed onthe upper plate 11 is arranged such that its outer surface is verticallyaligned with the edge of the upper plate 11.

A bonding member 18 is disposed between the outer surface of the sidewall 17 formed on the lower plate 12 and the lower surface of the sidewall 17 formed on the upper plate 11. Referring to FIGS. 3 and 4, it canbe found that the outer surface of the bonding member 18 is verticallyaligned with the outer edges of the upper and lower plates 11 and 12.

All the inner display cells 15 have the same size. On the other hand,the outermost display cells 15A have a size smaller than that of theinner display cells 15 because the side walls 17 formed with a printingtechnique and the bonding member 18 defining each outermost display celloccupy a certain area of the outermost display cell. Assuming that "A"indicated in FIG. 3 is the width of each inner display cell 15, "A1" thewidth of each outermost display cell 15A and "B" the width of thebonding part 20 constituted by the side walls 17 and the bonding member18, respectively, the actual width A1 of the outermost display cell 15Acan be expressed as follows: A1=A-B.

In order to make the light-emitting area of the outermost display cell15A approximate to that of the inner display cells 15 as much aspossible, the thickness of the second partition member 16A defining oneside surface of the outermost display cell 15A is reduced. That is, thewidth C1 of the second partition member 16A is smaller than the width Cof the first partition members 16 defining each inner display cell 15.In this case, the width reduction of the second partition member 16A isachieved at the portion of second partition member 16A facing theoutermost display cell 15A so that only the outermost display cell 15Acan increase in area without varying the area of the inner display cell15 adjacent to the outermost display cell 15A. As the second partitionmember 16A has a reduced width as mentioned above, the finally obtainedwidth A2 of the outermost display cell 15A becomes larger than the widthA1 by a length of "C-C1".

For minimizing the width of the bonding portion of plasma display panel10 constituted by the side wall members 17 and bonding member 18, thewidth of each side wall member 17 is smaller than that of the innerpartition members 16. It is preferred that the width B of the bondingportion 20 is not more than 1/3 the width A of inner display cell(B≦1/3). In some embodiments the bonding means (e.g. bonding member 18)has a width of not more than 1/3 to 1/5 of the width of the outermostdisplay cell. It is also preferred that the actual width C1 of thesecond partition member is not more than 1/2 to 1/4 of the width C ofthe first partition member (C1≦1/2C).

Although the outermost display cells 15A have been described as having asize smaller than that of the inner display cells 15 in theabove-mentioned embodiment, they may have the same size as the innerdisplay cells. In this case, the width A2 of the outermost display cell15A is identical to the width A of the inner display cell 15. This canbe achieved by making the reduced width, "C-C1", of the second partitionmember 16A identical to the length B of the bonding portion 20 inwardlyprotruded into the space between the upper and lower plates 11 and 12.

The side walls 17 defining the outermost display cell 15A maintain thecathode electrodes 13 at a constant height. In other words, the cathodeelectrodes 13 extend through the display cells 15A and 15 while passingover the side wall 17 formed on the lower plate 12. The side walls 17also serve to prevent the bonding member 18 from being protrudedinwardly of the plasma display panel upon pressing the bonding member tobond the upper and lower plates to each other after completing anattachment of the bonding member.

The cathode electrodes 13 and anode electrodes 14 are received ingrooves or holes provided at the lower plate 12 so that they are notprotruded outwardly of the plasma display panel.

INDUSTRIAL APPLICABILITY

In accordance with the present invention, the bonding portion 20, whichis disposed within the display area provided by the upper and lowerplates 11 and 12, is constituted by thin side wall members 17 and thinbonding member 18 to have a minimized width. Where a multi-screen isfabricated using plasma display panels including such a bonding portion,accordingly, it involves no or little generation of mosaic pattern dueto the connection boundary area 24. Therefore, it is possible to preventany picture distortion phenomenon upon connecting pictures. Where anoblique line is displayed, it is possible to minimize a degradation inthe continuity of the oblique line caused by the width of the connectionboundary area because the width of the connection boundary area in thecase of the present invention is smaller than that of the conventionalplasma display panels.

As apparent from the above description, the present invention provides aplasma display panel having a construction capable of providing a trimedge and maximizing the effective display area. Where plasma displaypanels having such a construction are used to constitute a multi-screen,it is possible to minimize generation of mosaic pattern, therebyavoiding any picture distortion phenomenon. Accordingly, naturalpictures of high quality can be produced.

We claim:
 1. A plasma display panel for a multi-screen comprising:anupper plate and a lower plate; a plurality of cathode electrodes andanode electrodes arranged so that they are spaced facing each otherbetween the upper and lower plates; a plurality of inner display cellsdefined within a display area provided between the upper and lowerplates by a plurality of spaced first partition members arranged betweenthe upper and lower plates, respectively, the inner display cells havingthe same area; outermost display cells arranged along edges of the upperand lower plates, each of the outermost display cells being definedbetween side wall means provided along the edges of the upper and lowerplates and a second partition member arranged between the upper andlower plates and spaced from the side wall means inwardly of the upperand lower plates, the second partition member having a reduced thicknessover that of each first partition member; and bonding means arrangedoutwardly of the side wall means and provided with an outer surfacevertically aligned with the edges of the upper and lower plates, thebonding means being adapted to bond the upper and lower plates to eachother.
 2. The plasma display panel in accordance with claim 1, whereineach of the outermost display cells has a size smaller than the size ofeach inner display cell by a size almost identical to the size of thebonding means.
 3. The plasma display panel in accordance with claim 2,wherein the side wall means is formed along the edges of the upper andlower plates using a printing method.
 4. The plasma display panel inaccordance with claim 1, wherein the reduction in thickness of thesecond partition member is achieved at a portion of the second partitionmember facing the corresponding outermost display cell.
 5. The plasmadisplay panel in accordance with claim 1, wherein the bonding means hasa width not more than 1/3 to 1/5 of the width of each outermost displaycell.
 6. The plasma display panel in accordance with claim 5, whereinthe second partition member has a width not more than 1/2 to 1/4 of thethickness of each first partition member.
 7. The plasma display panel inaccordance with claim 1, wherein each of the outermost display cells hasa size identical to the size of each inner display cell.
 8. The plasmadisplay panel in accordance with claim 3, wherein the side wall meanscomprises side wall members independently formed on the upper plate andthe lower plate.
 9. The plasma display panel in accordance with claim 8,wherein each of the side wall members formed on the lower plate isarranged at a place inwardly shifted a small distance from the edge ofthe lower plate such that the outer surface of the bonding means isvertically aligned with the edges of the upper and lower plates.